In electronic devices including displays, such as PCs and mobile phones, touch sensors, for example, touch pads are well known as one type of input devices that operate GUI screens displayed on the displays. In an information input device including a touch sensor, the user traces the touch sensor with a finger to enable moving of a cursor on the GUI screen, thus resulting in an intuitive GUI operation according to movement of the user's finger.
In addition to a location input operation of moving a cursor on a screen, the general GUI operations need an operation of determining an object such as an icon and a button on the screen, for example, an operation represented by a left click of a mouse.
The information input devices including the conventional touch sensors perform such an operation of determining an object by pressing a button placed near the touch sensor once or twice or by lightly tapping the surface of the touch sensor once or twice.
For example, any icon on a screen is selected and determined (executed) by (i) tracing the surface of the touch sensor with a finger to move a cursor on the screen to a target icon, (ii) once moving the finger away from the touch sensor, and (iii) pressing a button placed near the touch sensor twice or by lightly tapping the surface of the touch sensor twice.
In this case, since the user needs to move the finger away from the touch sensor at least once, there is a problem that the user cannot continuously and naturally move the finger.
Here, a clickable touch sensor is known as one of the solutions for improving the operability of a general touch sensor. The touch sensor is movable upward and downward, and includes a mechanical switch immediately underneath the touch sensor (See PTL 1).
The clickable touch sensor can select and determine an object on the GUI screen by pressing the touch sensor to press down the switch immediately underneath the touch sensor. For example, the user can select and determine (execute) any icon on the GUI screen by tracing the surface of the touch sensor, moving a cursor on the screen to the target icon, and pressing down the touch sensor.
In other words, such an information input device including a clickable touch sensor can continuously and naturally perform an operation without moving the finger away from the touch sensor, thus improving the operability of the user more than the conventional touch sensors.
While the operability has been improved, there are cases where, when the user presses a switch below a clickable touch sensor with the finger, the finger horizontally moves with the pressure and the position of the cursor is displaced (hereinafter referred to as “misclick”).
In particular, when the size of objects on the screen is small and a space between the adjacent objects is narrow, in the case where the position of the cursor is slightly displaced, an object near the target object is selected and determined, and erroneous operations frequently occur.
In order to solve the problem of the misclick on the clickable touch sensor, PTL 2 suggests a method for preventing the misclick, using an information input device including a touch sensor having variable flexibility with the pressure of a finger operation of the user.
FIG. 18 illustrates an information input system using a clickable touch sensor having the conventional misclick prevention function described in PTL 2.
As illustrated in FIG. 18, the information input system includes a clickable touch sensor 100, a touch information detecting unit 103, a screen display device 500, a cursor position calculating unit 106, a cursor display control unit 108, an object placement storage unit 109, an object display control unit 111, an object selection detecting unit 112, an object determining unit 113, and a cursor movement invalidating unit 114.
The clickable touch sensor 100 includes a touch sensor 101 and a mechanical switch 102.
The touch sensor 101 is a device having variable flexibility with the pressure of the user's finger in a pressing direction, and has a property of increasing the number of touch positions to be detected according to the magnitude of the pressure of the user's finger.
The switch 102 is placed vertically downward with respect to an operation surface of the touch sensor 101 (that is, back side of the touch sensor 101). When the user presses the touch sensor 101 with the pressure higher or equal to a predetermined value, the switch 102 is also pressed down to be turned ON.
The touch information detecting unit 103 detects a touch position when the user's finger is in contact with the touch sensor 101 and the number of touch positions corresponding to the pressure to the touch sensor 101.
The screen display device 500 includes a display screen, such as a liquid crystal display. On the display screen included in the screen display device 500, a GUI screen that is an operation screen of an electronic device operated by the clickable touch sensor 100 is displayed.
The cursor position calculating unit 106 calculates a position of a cursor on the GUI screen to be displayed on the screen display device 500.
The cursor display control unit 108 displays, on the GUI screen, a cursor at the position calculated by the cursor position calculating unit 106.
The object placement storage unit 109 stores object placement information of each object, such as an icon, a button, and a menu. The object placement information indicates how to place the object on the GUI screen.
The object display control unit 111 displays each object on the GUI screen based on the object placement information.
The object selection detecting unit 112 detects an object currently selected by the user from among a plurality of objects displayed on the GUI screen, based on the position of the cursor. The object determining unit 113 determines the object detected by the object selection detecting unit 112, when the user pressed the switch 102 of the clickable touch sensor 100.
When the user performs a determination operation on the object currently selected by the user, the cursor movement invalidating unit 114 detects a pressing operation of the user before the user presses the touch sensor 101 to turn ON the switch 102 and the pressing information is output, and invalidates movement of the cursor on the GUI screen during a period from detection of the pressing operation to turning OFF of the switch 102.
FIG. 19 is an external view of a GUI screen of a conventional information input device.
As illustrated in FIG. 19, a GUI screen 105 for operating an electronic device is displayed on the screen display device 500.
On the GUI screen 105, a cursor 107, and objects 110(a) to 110(c) are displayed.
The cursor 107 is displayed on the GUI screen 105, and is operated as a pointer by the information input device.
The operations performed by the information input system using a clickable touch sensor having the conventional misclick prevention function with the aforementioned configuration will be hereinafter described.
Here, a series of operations performed by the user who selects and determines (executes) the target object 110(b) from among the objects 110(a) to 110(c) placed on the GUI screen 105 displayed by the screen display device 500 will be described with reference to FIG. 19.
When the user traces the touch sensor 101 to move the cursor 107 displayed on the GUI screen 105, the touch information detecting unit 103 detects the position that is in contact with the user's the finger on the touch sensor 101.
The cursor position calculating unit 106 determines a position of the cursor 107 to be displayed on the GUI screen 105, based on the touch position obtained by the touch information detecting unit 103.
The cursor display control unit 108 displays, on the GUI screen 105, the cursor 107 at the position calculated by the cursor position calculating unit 106.
Furthermore, the object selection detecting unit 112 determines whether or not the cursor 107 is on the display area of the objects 110(a) to 110(c) by reading, from the object placement storage unit 109, the object placement information of each of the objects 110(a) to 110(c) displayed on the GUI screen 105 and comparing the object placement information with the position of the cursor obtained from the cursor position calculating unit 106.
For example, when the cursor 107 is on a display area of the object 110(b) as illustrated in the GUI screen of FIG. 19, the object selection detecting unit 112 determines that the cursor 107 is on the display area of the object 110(b) and outputs an ID number of the object 110(b) to the object display control unit 111.
Upon receipt of the ID number of the object 110(b) from the object selection detecting unit 112, the object display control unit 111 displays the object 110(b), for example, presents selection of the object 110(b) by changing the size and color of the object 110(b).
Furthermore, in order to determine the object 110(b) selected by the user, when the touch sensor 101 is pressed down to turn ON the switch 102, the switch 102 outputs the pressing information to the object selection detecting unit 112.
Upon receipt of the pressing information from the switch 102, the object selection detecting unit 112 outputs the ID number of the detected object 110(b) to the object determining unit 113.
Upon receipt of the ID number of the object 110(b) from the object selection detecting unit 112, assuming that the user determines the object 110(b), the object determining unit 113 outputs the ID number to the object display control unit 111 and performs a determination process corresponding to the object 110(b).
Upon receipt of the ID number of the object 110(b) from the object determining unit 113, the object display control unit 111 displays the object 110(b), for example, presents determination of the object 110(b) by changing the size and color of the object 110(b).
Since the touch sensor 101 is a device having the variable flexibility in a pressing direction as described above, although the touch information detecting unit 103 detects only one touch position when the user lightly touches the touch sensor 101 with the finger, it can detect a plurality of touch positions corresponding to a predetermined pressure or more when the finger presses the touch sensor 101 with the pressure.
The cursor movement invalidating unit 114 determines whether or not the number of touch positions obtained from the touch information detecting unit 103 is larger than or equal to a predetermined value, and outputs cursor movement invalidating information to the cursor position calculating unit 106 when the number is larger.
Upon receipt of the cursor movement invalidating information, the cursor position calculating unit 106 continues to hold the position of the cursor 107 before receipt of the invalidating information without change from its receipt.
In other words, the cursor movement invalidating unit 114 determines that the user will perform an operation of pressing down the switch 102 when the user presses the touch sensor 101 with a predetermined pressure or more, and invalidates change in the position of the cursor 107 after the determination.
Thus, even when the user's finger is horizontally displaced by the pressure of pressing the switch 102, the position of the cursor remains unchanged from the position before being pressed down. Thus, the cursor 107 is never horizontally displaced, or misclicked.